I have long figured that Dennis Kucinich may be a Gnome. But it recently occurred to me that there many be several politicians that have been replaced by Gnomes (if they're short politicians) or by two Gnomes standing on top of the other and wearing a mask. Gnomes are fairly good at disguise, after all.
The way to tell is if any have had a recent change of policies or displayed unusual behaviour, particularly regarding cookies or underpants. Of course, if they've always been weird or particularly in favour of murder (Karl Rove and Dick Cheney spring to mind here) they may have just always been Gnomish infiltrators in disguise.
And of course the truly shocking thing is that they hide in plain sight due to the human capacity to ignore anything that is believed to be "impossible"; how could someone who found out the terrible truth effectively warn anyone? It sounds "crazy", after all.
RPGpundit